TEMPE, Ariz. -- As fraternity brothers, friends and family of Jack Culolias band together, a long list of questions remain in the search for the missing Arizona State University freshman.

“I want the true story,” his stepmother, Renae Culolias, told 3TV.

His family pleaded with Tempe police Wednesday afternoon to bring in additional resources.

“We want the FBI involved and we want some answers,” Culolias said. “If it was your son or daughter, you’d feel the same way; there’s something wrong."

Jack Culolias, 19, was last seen at a Sigma Alpha Epsilon fraternity event at Cadillac Ranch at Tempe Marketplace Friday night. Police believe he was escorted out, but where he went next is still unknown, according to detectives.

“There are so many different stories, we don’t know which way to go,” said Grace Culolias, Jack’s mother.

An exhaustive search of the area around Salt River where a shoe believed to be Jack's was found by his mother on Tuesday turned up no new information Wednesday. Police said DNA testing is being conducted on the shoe. Investigators called it their best lead so far.

However, dive teams and special equipment including a robot with sonar and underwater cameras failed to produce any new signs of Jack.

“As of now, nothing has been located that says Jack is down in that area of the lake,” said Sgt. Mike Pooley with Tempe police.

Police also say surveillance video from Cadillac Ranch has not been helpful due to the number of people at the restaurant that night. A spokeswoman with Cadillac Ranch said the business is fully complying with the investigation, but she won’t go into details about the circumstances under which Jack left. Frat brothers insist he was alone, as he was brought out by a bouncer.

“We are hoping somebody will come forward,” Pooley said. “As of now there are other things that are happening right now as part of the investigation that I cannot go into detail on ... that are being worked as I speak.”

ASU police are assisting Tempe police with the investigation. A university spokeswoman said finding the missing student is their first priority, but added any allegations of misconduct by the fraternity will be investigated.

The national Sigma Alpha Epsilon organization issued a statement Wednesday offering their prayers and support to the Culolias family.

“We launch our own investigation anytime an incident with one of our chapters or members is brought to our attention,” said Brandon Weghorst, a spokesman for the national organization of SAE.

Weghorst said his organization is still trying to gather details from police and ASU officials. He said SAE has a zero tolerance policy for hazing and underage drinking at fraternity functions.

“It is the third party vendor’s responsibility to make sure laws and regulations are being complied with,” Weghorst said.

Owners and managers at Cadillac Ranch declined an interview.

Police and Jack's family are urging anyone with information to come forward.